MIC841 View Datasheet(PDF) - Micrel
Part Name
Description
Manufacturer
MIC841 Datasheet PDF : 8 Pages
| |||
Micrel, Inc.
VIN
VIN(HI)
VIN(LO)
0V
OUT
H AND N VERSIONS 0V
OUT
L VERSION
0V
VHYSTERISIS
Figure 2. Output Response and Hysteresis
Programming the MIC842 Thresholds
The voltage threshold is calculated using:
VIN(LO)
−
VREF
⎜⎛
⎝
R1 + R2
R2
⎟⎞
⎠
where:
VREF = 1.240V
MIC841/2
Input Transients
The MIC841/2 is inherently immune to very short
negative-going “glitches.” Very brief transients may
exceed the VIN(LO) threshold without tripping the output.
As shown in Figure 4, the narrower the transient, the
deeper the threshold overdrive that will be ignored by the
MIC841/2. The graph represents the typical allowable
transient duration for a given amount of threshold
overdrive that will not generate an output.
Figure 4. Input Transient Response
Figure 3. MIC842 Example Circuit
In order to provide the additional criteria needed to solve
for the resistor values, the resistors can be selected
such that they have a given total value, that is, R1 + R2
= RTOTAL. A value such as 1MΩ for RTOTAL is a
reasonable value because it draws minimum current but
has no significant effect on accuracy.
March 2011
7
M9999-030811-B
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